Magnetic suspension bearing

ABSTRACT

The present invention relates to a magnetic suspension bearing supported by magnetic force, which comprises one or more magnets fixed on a shaft directly or indirectly which can rotate with said shaft, and matching magnets provided in a certain space, wherein the magnetic polarity and magnitude of magnetic force of the matching magnets match with the magnetic polarity and magnitude of magnetic force of said one or more magnets to achieve the full suspension rotation of said shaft, and said magnets and/or matching magnets are permanent magnets. The present invention is of simple design and large power.

FIELD OF THE INVENTION

[0001] The present invention relates to a bearing, and more particularlyto a magnetic suspension bearing supported by magnetic force.

BACKGROUND OF THE INVENTION

[0002] There are two kinds of magnetic suspension bearings in the priorart: one is a permanent magnetic suspension bearing and the other is anelectromagnetic suspension bearing. In the electromagnetic suspensionbearing, the shaft is rotated in suspension corresponding to the bearingwith no frictional resistance and higher operation precision by amagnetic force induced by an electromagnetic field. However, thestructure of the bearing is very complicated, and it needs an electronicmeasurement and control system, auxiliary supporting means and otherauxiliary means, and accordingly, the manufacture cost is very high,especially for a bearing with a great load-bearing capability. Theconventional permanent magnetic suspension bearing is simple instructure and low in manufacture cost, but limited in load-bearingcapability and thereby mainly used in instruments such aselectromagnetism meters with monopole or two-pole magnetic suspensionand thereby a limited rigidity, namely a small dF/dz (the change rate ofthe load-bearing force when a gap changes), and therefore is not fit forvarious applications.

OBJECT OF THE INVENTION

[0003] The object of the present invention is to provide anall-permanent magnetic full suspension bearing with a simple structure,low manufacture cost, high stability, great rigidity and greatload-bearing capability which can be used widely in various fields.

SUMMARY OF THE INVENTION

[0004] To achieve the object mentioned above, the present inventionprovides a bearing which comprises one or more magnets fixed on a shaftdirectly or indirectly which can rotate with said shaft, and matchingmagnets provided in certain space, wherein the magnetic polarity andmagnitude of magnetic force of said matching magnets match with those ofsaid one or more magnets to achieve the full suspension rotation of saidshaft, wherein, said magnets and/or matching magnets are all permanentmagnets.

[0005] Said magnets and said matching magnets form at least two sets ofradial stable magnetic rings and at least one set of axial stablemagnetic rings provided between said radial stable magnetic rings,wherein said radial stable magnetic rings comprises a radial staticmagnetic ring formed by said matching magnets fixed to a bearing housingand a radial movable magnetic ring formed by said magnets which isparallel to the radial static magnetic ring and fixed to a shaft sleevewhich extends in radial direction, said radial static magnetic ring andsaid radial movable magnetic ring both comprise more than two crossmagnetic poles which are closely connected in the radial direction, themagnetic poles corresponding to said radial static magnetic ring andsaid radial movable magnetic ring along the radial direction have thesame magnitude of magnetic force with opposite polarities; said axialstable magnetic ring comprises an axial static magnetic ring formed bysaid matching magnets fixed to a bearing housing and an axial movablemagnetic ring formed by said magnets which is parallel to the axialstatic magnetic ring and fixed to a shaft sleeve which extends in theaxial direction, both said axial static magnetic ring and said axialmovable magnetic ring comprise more than two cross magnetic poles whichare closely connected in the axial direction, the magnetic polescorresponding to said axial static magnetic ring and said axial movablemagnetic ring along the axial direction have the same magnitude ofmagnetic force with opposite polarities.

[0006] According to the present invention, said closely connected crossmagnetic poles are formed by jointing two or more ring-shaped permanentmagnets together, each one of the ring-shaped permanent magnets is asingle ring-shaped permanent magnet.

[0007] According to the present invention, said closely connected crossmagnetic poles are formed by jointing two or more ring-shaped permanentmagnets together, each one of the ring-shaped permanent magnets isformed by sticking two or more permanent magnetic blocks together.

[0008] According to the present invention, said closely connected crossmagnetic poles are formed by way of a multiple-pole magnetizing method.

[0009] According to the present invention, said closely connected crossmagnetic poles have four magnetic poles.

[0010] [According to another aspect of the present invention, itprovides a bearing which comprises one or more magnets fixed on theshaft directly or indirectly which can rotate with said shaft, andmatching magnets provided in a certain space, wherein the magneticpolarity and magnitude of magnetic force of the matching magnets matchwith the magnetic polarity and magnitude of magnetic force of said oneor more magnets to realize the complete magnetic suspension rotation ofsaid shaft.

[0011] According to the present invention, said magnets and/or matchingmagnets are permanent magnets.]

[0012] In the present invention, due to the fact that one or morepermanent magnets are fixed on the shaft directly or indirectly, andmatching permanent magnets are provided in certain space, wherein themagnetic polarity and magnitude of magnetic force of said matchingmagnets match with those of said one or more magnets, such perfectmatching in space makes the rotating shaft with permanent magnet fixedthereon to rotate in full suspension with all-permanent magnet bymagnetic force without other kinds of support or repulsion, in otherwords, full magnetic suspension can be achieved with the perfectcombination of permanent magnets solely without a complicated electroniccontrol system, auxiliary supporting means, such as that made ofsuperconductor, and other auxiliary means. Accordingly, the presentinvention has many advantages such as a simple structure, lowmanufacture cost, high stability, great rigidity and great load-bearingcapacity, and can be used widely in various fields.

[0013] According to the present invention, in each one of the radialstable magnetic ring sets, the magnetic poles corresponding to saidradial static magnetic ring and said radial movable magnetic ring alongthe radial direction have the same magnitude of magnetic force withopposite polarities. Similarly, in each one of the axial stable magneticring sets, the magnetic poles corresponding to said axial staticmagnetic ring and said axial movable magnetic ring along the axialdirection have the same magnitude of magnetic force with oppositepolarities. In this way, pushing and pulling magnetic circuits, i.e.attracting and repelling magnetic circuits, are formed in both theradial direction and the axial direction respectively. Namely, each setof the radial stable magnetic rings and the axial stable magnetic ringsare at the lowest energy state when the magnetic poles are in couplingstate, and a restoring force will be produced when they are departurefrom the coupling state. In regard to the axial stable magnetic ring, anaxial stablizing force is formed in axial direction so that the shaftwill not move in axial direction, but the axial stable magnetic ringcould not maintain the shaft stable in radial direction. In regard tothe radial stable magnetic ring, because the gravity of the shaft willmake the radial movable magnetic ring have a tendency to move downward,the radial static magnetic ring will pull the radial movable magneticring upward by a coupling force, and therefore an upward supportingforce is formed. Thus, the radial stable magnetic ring makes the shaftstable in radial indirection. However, the radial stable magnetic ringcould not make the shaft stable in axial direction. When the alternativeaxial stable magnetic ring and radial stable magnetic ring cooperatewith each other, the shaft can be suspended entirely and meet therequirements of the stability and rigidity by taking into account ofother factors, such as gravity. With directly employing the magneticsuspension structure of the present invention, a magnetic suspensionbearing with the advantages of simple structure, low manufacture cost,good stability and great rigidity can be manufactured. Since therigidity is increased with the increase of the number of the magneticpoles, and the number of the poles can be determined according to therequirement of the rigidity, therefore, a magnetic suspension with greatrigidity can be manufactured and the present invention can be applied tovarious fields.

[0014] According to the present invention, said magnet as mentionedabove is each one of the single ring-shaped permanent magnets which formsaid cross magnetic poles of the axial movable magnetic ring in theaxial stable magnetic ring, or is each one of the single ring permanentmagnets which form said cross magnetic poles of the radial movablemagnetic ring in the radial stable magnetic ring. Wherein, said magnetis indirectly fixed to the shaft via a bearing housing. Said matchingmagnet mentioned above is each one of the single ring-shaped permanentmagnets which form said cross magnetic poles of the axial staticmagnetic ring in the axial stable magnetic ring, or is each one of thesingle ring-shaped permanent magnets which form said cross magneticpoles of the radial static magnetic ring in the radial stable magneticring.

[0015] The present invention will be further described with thefollowing embodiments accompanying with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016]FIG. 1 illustrates the structure in accordance with the firstembodiment of the present invention;

[0017]FIG. 2 illustrates the structure in accordance with the secondembodiment of the present invention;

[0018]FIG. 3 illustrates the structure in accordance with the fourthembodiment of the present invention;

[0019]FIG. 4 illustrates the structure in accordance with the fifthembodiment of the invention;

[0020]FIG. 5 is a cross-sectional view taken along the middle magneticpoles in FIG. 4;

[0021]FIG. 6 is a schematic view of the polarity taken from thecross-section B-B in FIG. 5.

DETAILED DESCRIPTION OF THE INVENTION

[0022] The First Embodiment

[0023] As shown in FIG. 1, two sets of radial stable magnetic rings 2are provided on a supported shaft 1. One set of axial stable magneticrings 3 is provided between the two sets of radial stable magnetic rings2. The radial stable magnetic rings 2 comprise a radial static magneticring 4 and a radial movable magnetic ring 5, which are parallel to eachother. The radial static magnetic ring 4 is fixed on a bearing housing6. The radial movable magnetic ring 5 is fixed on a shaft sleeve 7 whichextends in radial direction. The shaft sleeve 7 is integrated with theshaft 1. Four closely connected cross magnetic poles are alternativelyprovided in the radial static magnetic ring 4, which are S pole, N pole,S pole and N pole from the shaft along the radial directionrespectively. Four closely connected cross magnetic poles arealternatively provided in the radial movable magnetic ring 5, which areN pole, S pole, N pole and S pole from the shaft along the radialdirection respectively. The closely connected cross magnetic polesmentioned above can be formed by a single ring-shaped permanent magnet,or by a multiple-pole magnet formed by the way of a multiple-polemagnetizing method. Since it is difficult to manufacture a largermagnetic ring, the closely connected cross magnetic poles mentionedabove can be formed by sticking a plurality of magnetic blocks togetherto achieve the magnetic suspension at a larger level. When the shaft 1rotates, the shaft sleeve 7 rotates the radial movable magnetic ring 5fixed thereon. Because the bearing housing 6 is stationary, the radialstatic magnetic ring 4 fixed on the bearing housing 6 is alsostationary. Because the polarity of the magnetic pole corresponding tothe radial static magnetic ring 4 is opposite to the polarity of themagnetic pole corresponding to the radial movable magnetic ring 5 butthey have the same magnitude of magnetic force, when they are incoupling state, the energy state is at the lowest. When the gravity ofthe shaft makes the shaft 1 and the radial movable magnetic ring 5departure downwards from the coupling state, the radial static magneticring 4 makes the shaft 1 and the radial movable magnetic ring 5 returnto the coupling position where the energy state is at the lowest by arestoring force of multiple-pole magnetic force so that the magneticenergy is at the lowest, namely it is stable in the radial direction.

[0024] The axial stable magnetic ring 3 comprises an axial staticmagnetic ring 8 and an axial movable magnetic ring 9, which are parallelto each other. The axial static magnetic ring 8 is fixed on an axialbearing housing 10. Both the bearing housing 6 and axial bearing housing10 are fixed in a base. The axial movable magnetic ring 9 is fixed on anaxial shaft sleeve 11 which extends in the axial direction. The axialshaft sleeve 11 is integrated with the shaft 1. Four closely connectedcross magnetic poles are alternatively provided in the axial staticmagnetic ring 8, which are N pole, S pole, N pole and S pole from rightto left in the axial direction respectively. Four closely connectedcross magnetic poles are alternatively provided in the axial movablemagnetic ring 5, which are S pole, N pole, S pole and N pole from rightto left along the axial direction respectively. The closely connectedcross magnetic poles mentioned above can be formed by the combination ofsingle ring-shaped permanent magnets, or by a multiple-pole magnetformed by way of a multiple-pole magnetizing method. Since it isdifficult to manufacture a larger magnetic ring, the closely connectedcross magnetic poles mentioned above can be formed by sticking aplurality of magnetic blocks together to achieve the magnetic suspensionat a larger level. When the shaft 1 rotates, the axial shaft sleeve 11rotates the axial movable magnetic ring 9 fixed thereon. Because theaxial bearing housing 10 is stationary, the axial static magnetic ring 8fixed on the axial bearing housing 10 is also stationary. Because thepolarity of the multiple-pole of the axial static magnetic ring 8 isopposite to the corresponding polarity of the multiple-pole of the axialmovable magnetic ring 9 but they have the same magnitude of magneticforce, when they are in coupling state, the energy state is at thelowest, namely it is stable in axial direction.

[0025] Magnetic potential energy is defined as the value of energy thatis yielded by the relative position change of magnetic field. When themagnets are brought together, like poles repel, i.e. their N-N polesrepel or their S-S poles repel, the change of gap between the polesleads to the change of positive magnetic potential energy. Similarly,when the magnets are brought together, opposite poles attract, i.e.their N-S poles attract or their S-N poles attract, the change of gapbetween the poles leads to the change of negative magnetic potentialenergy. The two kinds of changes of energy will be limited only inpositive range or in the negative range, and the unbalance forcesproduced thereby are eccentric forces. In other words, radial stablemagnetic rings make the shaft unstable in axial direction and axialstable magnetic rings make the shaft unstable in radial direction, andthe unbalance forces produced thereby are eccentric forces. When therelative position of corresponding cross magnetic poles changes to samepoles facing each other from the position where the opposite poles faceeach other, that is, from N-S poles to N-N or S-S poles, the change ofmagnetic potential energy produced thereby is from negative to positive,which is far more than the change only in positive range or in negativerange, and thereby restoring force tending to the coupling state is farmore than the eccentric force. In conclusion, the restoring force, withwhich the radial stable magnetic ring makes the shaft stable in radialdirection, is far more than the eccentric force, with which the axialstable magnetic ring makes the shaft unstable in radial direction.Similarly, the restoring force, with which the axial stable magneticring makes the shaft stable in axial direction, is far more than theeccentric force, with which the radial stable magnetic ring makes theshaft unstable in axial direction. Thus, in this embodiment, when theshaft in suspension is achieved, the restoring forces, which made theshaft back into the state of stable suspension, are far more than theeccentric forces, which made the shaft unstable in axial direction andin radial direction, accordingly, the shaft can be in suspension stably.

[0026] Each single ring-shaped permanent magnet in axial stable magneticring 3 in FIG. 1 which forms cross magnetic poles of axial movablemagnetic ring 9, and each single ring-shaped permanent magnet in radialstable magnetic ring 2 which forms cross magnetic poles of radialmovable magnetic ring 5 are both said magnets defined above which arefixed to shaft 1 indirectly via shaft sleeve 7. Said matching magnets,which is fixed on bearing housing 6 and whose polarities are opposite tothose of said magnet with certain gap between them, are each of thesingle ring-shaped permanent magnets in axial stable magnetic ring 3which forms cross magnetic poles of axial static magnetic ring 8, andeach of the single ring-shaped permanent magnets in radial stablemagnetic ring 2 which forms cross magnetic poles of radial staticmagnetic ring 4.

[0027] Therefore, the magnetic suspension structure in this embodimentcan achieve stability in both axial and radial directions and therebyachieve the object of the present invention.

[0028] By calculating the parts to be supported, the two sets of theradial stable magnetic rings 2 and one set of the axial static magneticrings 3 provided between the two sets of the radial stable magneticrings in this embodiment can bear the weight in the following range:weight of shaft is 50 kg and the rigidity is 500 kg/mm. Bearings withgreater load-bearing capacity and rigidity than those of electromagneticsuspension bearings can be made with the combination of multiple sets.

[0029] The Second Embodiment

[0030] In this embodiment, four sets of radial stable magnetic rings 2and two sets of axial stable magnetic rings 3 are provided with anarrangement as shown in FIG. 2. The two sets of axial stable magneticrings 3 are provided between the two sets of the radial stable magneticrings 2, respectively. The radial static magnetic rings 4 of the twocentral sets of the radial stable magnetic rings 2 are fixed on the twosides of the same bearing housing along radial direction. There are alsofour cross magnetic poles in this embodiment. Compared with the firstembodiment, it can bear bigger rotating shaft and has greaterload-bearing capacity and rigidity in this embodiment.

[0031] The Third Embodiment

[0032] Compared with the first embodiment, the number of the magneticpoles of each the individual radial and axial magnetic ring is increasedfrom 4 to 6. Therefore, the magnetic suspension is more powerful.

[0033] The Fourth Embodiment

[0034] Referring to FIG. 3, there is only one magnet, that is, anadaxial ring-shaped permanent magnet 11 is fixed to the shaft 1 viamagnetizer 13 which is fixed on shaft 1. There are three matchingmagnets: an abaxial ring-shaped permanent magnet 12 fixed on aring-shaped magnetizer 13, which has the same polarity and magnitude ofmagnetic force as the ring-shaped permanent magnet 11, and a left sidering-shaped permanent magnet 14 and a right side ring-shaped permanentmagnet 15 provided on each side of said abaxial ring-shaped permanentmagnet respectively, which are fixed on said magnetizer 13 and have thesame polarity as said abaxial ring-shaped permanent magnet. Thering-shaped magnetizer 13 is coaxial with the shaft 1 but the diameterof the magnetizer 13 is bigger than that of the shaft 1 and thereby aring-shaped gap is formed between the magnetizer 13 and the shaft 1. Inthis embodiment, because of the existence of magnetizer 13, though theadaxial ring-shaped permanent magnet 11 and the abaxial ring-shapedpermanent magnet 12 have the same polarity and they repel each other,the distance therebetween caused by the repulsion will be at a value ofd1 at most. Thus, the shaft 1 is stable in radial direction, but ismovable in axial direction. A left side ring-shaped permanent magnet 14and a right side ring-shaped permanent magnet 15, which have the samepolarity, are provided on the magnetizer 13 respectively at a distanced2 from the left side and the right side of the abaxial ring-shapedpermanent magnet 12. By calculating the value of the distances d1 and d2and the magnitude of the magnetic force, the adaxial ring-shapedpermanent magnet 11, which tends to move in axial direction, can be madestable. In this embodiment, the external magnetic circuit and aninternal magnetic circuit are cylindrical. The repulsion between thecentral magnet and one matching magnet make the shaft unstable in axialdirection and stable in radial direction. Two magnetic circuits areformed between another two matching magnets provided on the two sidesand the central matching magnet respectively, when there is adisplacement rightwards for shaft 1 the right side magnet producesrepulsion, which can be decomposed to leftward thrust pushing shaft 1leftwards and downward repulsion making the shaft stable in radialdirection, and thereby stability in axial direction is achieved.Therefore, a full magnetic suspension can be achieved.

[0035] The Fifth Embodiment

[0036] Referring to FIGS. 4-6. FIG. 4 is a plane all-permanent magneticfull suspension bearing. In this embodiment, said magnets are twocylindrical magnets 16 and 17 having the same polarity and magnitude ofmagnetic force which are provided in the centers of the basins of thetwo circular-basin-shaped magnetizers 13 face to face. As shown in FIG.5, the cylindrical magnets 16 and 17 form a strong magnetic field in asmall span, and therefore a suspension force (i.e. repulsion force) isproduced. The matching magnets are two arc magnets which arerespectively fixed on the edges of the basins of the two magnetizers 13and formed into two hollow cylindrical multiple-pole magnets 18 and 19.The corresponding magnetic poles of the two hollow cylindricalmultiple-pole magnets 18 and 19 have the same magnitude of magneticforce with opposite directions, as shown in FIG. 6, and the magneticpoles have big span and small magnetic field to form an attractive forceand pushing and pulling magnetic circuits in radial and axial directionsto keep the circuits stable in axial direction and radial direction andform a plane permanent magnetic full suspension bearing. The shaft inthis embodiment is fixed in the central bottom of the twocircular-basin-shaped magnetizers 13. In this embodiment, N-poles andS-poles in FIG. 6 can be provided alternately with each other in radialdirection in a ring.

INDUSTRIAL APPLICABILITY

[0037] The magnetic suspension bearing of the present invention can beapplied in various fields where a bearing with high stability, a greatrigidity and great load-bearing capability is needed.

1. A magnetic suspension bearing, characterized in that the bearingcomprises one or more magnets fixed on a shaft directly or indirectlywhich can rotate with said shaft, and matching magnets provided incertain space, wherein the magnetic polarity and magnitude of magneticforce of the matching magnets match with the magnetic polarity andmagnitude of magnetic force of said one or more magnets to achieve thefull suspension rotation of said shaft, and that said magnets and/ormatching magnets are permanent magnets.
 2. The magnetic suspensionbearing as claimed in claim 1, characterized in that said magnets andsaid matching magnets form at least two sets of radial stable magneticrings and at least one set of axial stable magnetic rings providedbetween said radial stable magnetic rings, wherein said radial stablemagnetic ring comprises a radial static magnetic ring formed by saidmatching magnets fixed to a bearing housing and a radial movablemagnetic ring formed by said magnets which is parallel to the radialstatic magnetic ring and fixed to a shaft sleeve which extends in radialdirection, said radial static magnetic ring and said radial movablemagnetic ring both comprise more than two cross magnetic poles which areclosely connected in the radial direction, the magnetic polescorresponding to said radial static magnetic ring and said radialmovable magnetic ring along the radial direction have the same magnitudeof magnetic force with opposite polarities; said axial stable magneticring comprises an axial static magnetic ring formed by said matchingmagnets fixed to a bearing housing and an axial movable magnetic ringformed by said magnets which is parallel to the axial static magneticring and fixed to a shaft sleeve which extends in the axial direction,both said axial static magnetic ring and said axial movable magneticring comprise more than two cross magnetic poles which are closelyconnected in the axial direction, the magnetic poles corresponding tosaid axial static magnetic ring and said axial movable magnetic ringalong the axial direction have the same magnitude of magnetic force withopposite polarities.
 3. The magnetic suspension bearing as claimed inclaim 2, characterized in that said closely connected cross magneticpoles are formed by jointing two or more ring-shaped permanent magnetstogether, each one of the ring-shaped permanent magnets is a singlering-shaped permanent magnet.
 4. The magnetic suspension bearing asclaimed in claim 2, characterized in that said closely connected crossmagnetic poles are formed by jointing two or more ring-shaped permanentmagnets together, that each one of the ring-shaped permanent magnets isformed by sticking two or more permanent magnetic blocks together. 5.The magnetic suspension bearing as claimed in claim 2, characterized inthat said closely connected cross magnetic poles are formed by way of amultiple-pole magnetizing method.
 6. The magnetic suspension bearing asclaimed in claim 2, characterized in that said closely connected crossmagnetic poles have four magnetic poles.
 6. A magnet suspension bearing,characterized in that the bearing comprises one or more magnets fixed ona shaft directly or indirectly which can rotate with said shaft, andmatching magnets provided in a certain space, wherein the magneticpolarity and magnitude of magnetic force of the matching magnets matchwith the magnetic polarity and magnitude of magnetic force of said oneor more magnets to realize the complete magnetic suspension rotation ofsaid shaft.
 7. The magnetic suspension bearing as claimed in claim 6,characterized in that said magnets and/or matching magnets are permanentmagnets.
 7. The magnetic suspension bearing as claimed in claim 1,characterized in that said magnets is an adaxial ring-shaped permanentmagnet fixed on the shaft directly or indirectly, there are threematching magnets, an abaxial ring-shaped permanent magnet fixed on aring-shaped magnetizer, which has the same polarity and magnitude ofmagnetic force as said adaxial ring-shaped permanent magnet, a left sidering-shaped permanent magnet and a right side ring-shaped permanentmagnet provided on the each side of said abaxial ring-shaped permanentmagnet respectively, which are fixed on said magnetizer and have thesame polarity as said abaxial ring-shaped permanent magnet.
 8. Themagnetic suspension bearing as claimed in claim 1, characterized in thatsaid magnets are two cylindrical magnets having the same polarity andmagnitude of magnetic force provided respectively in central bottoms oftwo circular-basin-shaped magnetizers face to face, said matchingmagnets are two arc magnets which are respectively fixed on the edges ofthe basins of the two magnetizers and form into two hollow cylindricalmultiple-pole magnets, and that the corresponding magnetic poles of thetwo hollow cylindrical multiple-pole magnets have the same magnitude ofmagnetic force with opposite directions.